Transfer assembly for presses



TRANSFER ASSEMBLY FOR PRESSES Filed Oct. 16. 1967 5 Sheets-Sheet 2 a 2377/7 g5 Z4 55 77 J07 65 30 554 I I I l //1/l /V7"0/?. FREDEP/CK H.8/44/72 1 W Ti 5 July 22, 1969 F. H. BAUTZ TRANSFER ASSEMBLY FOR PRESSES5 Sheets-Sheet 5 Filed Oct. 16, 1967 July 22, 1969 F. H. BAUTZ 3,456,814

TRANSFER ASSEMBLY FOR PRESSES Filed Oct. 16, 196'? 5 Sheets-Sheet 4 N gR4 w \kko iii!!! 4;. I 2 w l i 5 :3 m 3 1 m g F N wvavrae.

AWMW July 22, 1969 BAUTZ 3,456,814

I TRANSFER ASSEMBLY FOR PRESSES Filed Oct. 16, 1967 5 Sheets-Sheet 5 Iam/ W "H3 5 3,456,814 TRANSFER ASSEMBLY FOR PRESSES Frederick H. Bautz,Hazel Crest, Ill., assignor to Verson Allsteel Press Company, Chicago,Ill., a corporation of Delaware Filed Oct. 16, 1967, Ser. No. 675,543Int. Cl. B66c 23/10 US. Cl. 214-1 15 Claims ABSTRACT OF THE DISCLOSURE Atransfer assembly is provided for a press for gripping and transferringwork pieces from station to station along the press. It includes atleast one longitudinally movable feed bar and at least one grippermechanism carried by said at least one feed bar for longitudinallymoving gripper finger mechanisms having gripper fingers to grip andrelease the work pieces for transferring the work pieces as said atleast one feed bar is longitudinally moved. The gripper mechanismslaterally advance and retract the gripper finger mechanisms and open andclose the gripper fingers thereof. Said at least one feed bar is alsoraised and lowered by a lifter mechanism. In operation, the feed barsare in their lowered position, and the gripper finger mechanisms arethen laterally advanced and the fingers are closed to grip the workpiece. The feed bars and gripper finger mechanisms are then raised,longitudinally moved in one direction and then lowered to transfer thework piece from one station to the next. The gripper fingers are thenopened and the gripper finger mechanisms are then laterally retractedand longitudinally returned in the opposite direction by the loweredfeed bar for another cycle of operation. The lifter mechanisms supportthe feed bars at a plurality of points along the length thereof.

A principal object of this invention is to provide improved liftermechanisms in the foregoing transfer as sembly for lowering and raisingthe longitudinally movable feed bars. Briefly, in this connection, eachlifter mechanism includes a lifter housing carried by the press, aplunger vertically slidably mounted in the housing and extendingupwardly therefrom, and a bracket carried by the upper end of theplunger and having supporting and guiding rollers thereon. Thelongitudinally movable feed bars are provided with guide tracks whichare engageable with said supporting and guiding rollers to be supportedthereby. Means are provided for raising and lowering the plunger forraising and lowering the feed bars. The raising and lowering means maybe gear and rack means as specifically disclosed herein. Means are alsoprovided for supplying air under pressure below the plungers so thatmuch of the load carried by the plungers (the feed bars, the grippermechanisms, the gripper finger mecha nisms, and the Work pieces) issupported by such air under pressure. Such a lifter mechanism, thedetails of which are disclosed herein, is particularly suitable for usein the transfer assembly disclosed herein, it being simple inconstruction and accurate in operation and it being rugged for long lifeoperation.

Other objects of this invention reside in the combination of thetransfer assembly incorporating the aforementioned lifter mechanisms andincluding means for operating the lifter mechanisms, means forlongitudinally moving the feed bars in one direction and the oppositedirection, and means for operating the gripper mechanisms to advance andretract the gripper finger mechanisms and to open and close the gripperfingers thereof all in timed relation.

The specific gripper mechanisms for laterally advancing and retractingthe gripper finger mechanisms and for States Patent 3,456,814 PatentedJuly 22, 1969 closing and opening the gripper fingers thereof isdisclosed and claimed in Frederick H. Bautz and Howard J. Mc- Elroyapplication Ser. No. 675,625 filed Oct. 16, 1967. The specific gripperfinger mechanisms for gripping and releasing the work pieces aredisclosed and claimed in Frederick H. Bautz and Tsuruo Otsukaapplication Ser. No. 675,544, filed Oct. 16, 1967.

Further objects and advantages of this invention will become apparent tothose skilled in the art upon reference to the accompanyingspecification, claims and drawings in which:

FIG. 1 is a diagrammatic front elevational view of a conventionalmechanical press having the transfer assembly of this invention appliedthereto;

FIG. 2 is a diagrammatic horizontal sectional view through the press ofFIG. 1 taken substantially along the line 22 of FIG. 1;

FIG. 3 is a chart illustrating the motions applied to the gripper fingermechanisms of the transfer assembly for transferring work pieces fromone station to the next station in the press;

FIG. 4 is a top plan view of one portion of the transfer assemblydiagrammatically illustrated in FIG. 2;

FIG. 5 is an elevational view of one portion of the transfer assemblyillustrated in FIG. 1;

FIG. 6 is an elevational 'view of a portion of the transfer assemblyillustrated in FIG. 5 with parts of the lifter mechanism shown insection;

FIG. 7 is an endelevational view of a portion of the transfer assemblylooking from the right of FIG. 6 with the lifter mechanism thereof insection along the line 77 of FIG. 6;

FIG. 8 is a vertical sectional view through the gripper mechanism of aportion of the transfer assembly taken substantially along the line 8-8of FIG. 6;

FIG. 9 is a horizontal sectional view through the gripper mechanismtaken substantially along the line 9-9 of FIG. 8;

FIG. 10 is a vertical sectional view through the gripper mechanism takensubstantially along the line 1010 of FIG. 8;

FIG. 11 is a horizontal sectional view through the gripper mechanismtaken substantially along the line 11-11 of FIG. 9 and illustrating theactuator rods in the retracted position;

FIG. 12 is a horizontal sectional view similar to FIG. 11 butillustrating the actuator rods advanced to substantially the advancedposition;

FIG. 13 is a horizontal sectional view similar to FIGS. 11 and 12 butillustrating the second actuator rod being advanced beyond the advancedposition toward the projected position; and

FIG. 14 is an elevational view of a splined ring utilized in securingthe gripper finger mechanism to the gripper mechanism.

Referring first to FIGS. 1 and 2, a conventional press, such as amechanical press, is diagrammatically illustrated at 10. It includes abed 11, uprights 12 supporting a crown (not shown) and a verticallyreciprocatable ram 13 which may be driven from a power driven crankshaft(not shown). Arranged along the length of the bed 11 is a plurality ofspaced apart work forming stations, each including a die structure 14carried by an adapter plate 11A and bolster on the bed 11 and a punchstructure 15 including an adapter plate carried by the ram 13 forperforming work functions on work pieces upon each downward stroke ofthe press ram 13 as they are progressively advanced along the press 10from station to station. The initial work pieces are fed to the press 10from a magazine 16 at one end of the press and the finished work piecesare discharged from the press 10 by a discharge mechanism 17, such as aconveyor or a chute or the like,

at the other end of the press 10. The work pieces are progressivelytransferred from station to station in the press from the magazine 16 tothe discharge mechanism 17.

The press is provided with a transfer assembly generally designated at18 and extending lengthwise of the press. The transfer assembly 18includes at least one longitudinally movable feed bar 19 (two beingillustrated with one toward the front of the press and the other towardthe rear of the press) which carry a plurality of equally spaced grippermechanisms 20. Each gripper mechanism 20 laterally advances and retractsa gripper finger mechanism 21 and opens and closes the gripper fingersof the gripper finger mechanism for gripping and releasing the Workpieces being formed by the press. The transfer assembly 18 also includesa plurality of lifter mechanisms 22 carried by the adapter plate 11A onthe bed 11 for supporting and raising and lowering the longitudinallymovable feed bars 19.

A pair of longitudinally extending reciprocatable rods 23 is providedfor longitudinally moving the feed bars 19 in one direction and in theopposite direction. A pair of longitudinally extending reciprocatablerods 24 is provided for operating the gripper mechanisms 20 to advanceand retract the gripper finger mechanisms 21 and to open and close thegripper fingers thereof. A pair of longitudinally extendingreciprocatable rods 25 is provided for operating the lifter mechanisms22 to raise and lower the feed bars 19 and hence the gripper mechanisms20 carried thereby. A suitable drive mechanism 26, which is operatedfrom the crankshaft of the press 10 in timed relation therewith, isarranged at one end of the press 10 for reciprocating the rods 23, 24and 25 in timed relation to each other and to the upward and downwardmovement of the press ram 13.

The motions imparted to the gripper finger mechanisms 21 fortransferring the work pieces from the magazine 16 and progressively fromstation to station along the press 10 to the discharge mechanism 17 arediagrammatically illustrated in FIG. 3. With the parts in the positionsillustrated in FIGS. 1 and 2, the ram 13 has been raised sufficiently sothat the punches carried thereby are clear from the work pieces, thefeed bars 19 are in their lowered and their returned positions, and thegripper fiinger mechanisms 21 are in their retracted positions withtheir fingers opened. This is represented by the point A in the diagramof FIG. 3.

First, the rods 24 are moved to the left with respect to the feed bars19 to advance laterally the gripper finger mechanisms and close thefingers thereof to grip the work piece in that station. Next, the rodsare moved to the left to raise the feed bars 19 and hence the gripperfinger mechanisms 20 to lift the gripped work piece from the diestructure of that station. Next, the rods 23 and 24 are simultaneouslymoved to the left to move the raised feed bars 19 to the left totransfer the gripped and raised work piece from that station to the nextstation, there being no relative movement between the rods 23 and 24during this movement. Next, the rods 25 are moved in the oppositedirection to the right to lower the feed bars 19 and hence the gripperfinger mechanisms 20 for lowering the gripped work piece into the diestructure 14 of said next station. Next, the rods 24 are moved in theopposite direction to the right to open the gripper fingers in thegripper mechanisms 20 and retract the gripper finger mechanisms. Next,the rods 23 and 24 are simultaneously moved in the opposite direction tothe right to move the lowered feed bars 19 to the right to return thegripper finger mechanisms 21 with their fingers in opened position topoint A in FIG. 3 for another transferring cycle. The punches 15 on theram 13 perform their workfunctions on the work pieces While the gripperfinger mechanisms 20 are lowered and retracted. The drive mechanism 26may include suitable cam linkage and lever constructions operated fromthe crankshaft of the press 10 for producing the foregoing timedsequences of operation of the 4 rods 23, 24 and 25 with respect to theoperation of the press ram 13.

While the transfer assembly 18 is illustrated in FIGS. 1 to 3 as havingtwo sets of mechanisms, one toward the front of the press and the othertoward the rear, for gripping the work pieces at two points fortransferring them along the press, in some instances it may be desirableto grip the work pieces at only one point for this purpose and, undersuch circumstances, only one set of mechanisms need be used, as forexample, the one toward the front of the press or the one toward therear thereof. The constructions of the lifter mechanisms 22 and thegripper mechanisms 20 are generally illustrated in FIGS. 4 to 7, thedetails of the lifter mechanisms 22 being illustrated in FIGS. 6 and 7and the details of the gripper mechanisms being illustrated in FIGS. 8to 13.

Referring now to FIGS. 4 to 7 the lifter mechanism, generally designatedat 22, includes a lifter housing 30' which is suitably secured to thetop of the adapter plate 11A on the bed structure 11. It has adownwardly extending projection 31 which is accommodated by an opening32 in the adapter plate 11A. The adapter plate 11A in addition tocarrying the lifter housing 30 also carries the die structures 14 sothat the transfer assembly 18 and the die structures 14 are a unitizedassembly which may be removed and replaced as a unit, the adapter platebeing removable from the bolster and the bed 11 for this purpose. Thehousing 31 has a vertically arranged cylindrical opening 33 therethroughand a bearing sleeve 34 is arranged at the top of the opening and abearing sleeve 35 is arranged toward the bottom of the opening butspaced upwardly therefrom. The opening 33 is closed at its bottom by aplate 36 suitably secured to the downward extension 31 of the housing30. A plunger 37 is vertically slidably mounted by the bearing sleeves34 and 35 in the opening 33 and it is provided at its upper extremitywith a flange 38. Adjacent its lower end the plunger 37 is provided witha seal 39 for sealing the plunger with respect to the bearing sleeve 35.

A- bracket 41 is secured to the flange 38 at the upper end of theplunger 37 and this bracket 41 carries four rollers 42 rotatable aboutvertical axes, two rollers 43 rotatable about horizontal axes and tworollers 44 rotatable about horizontal axes. These rollers cooperate witha track 45 secured to the underside of the longitudinally movable feedbars 19. The track 45 extends laterally from the feed bars 19 so as tobe laterally engaged by the rollers 42 and vertically engaged by therollers 43 and 44. As a result, the track 45 and, hence, the feed bars19 are supported and guided for longitudinal movement by the rollers 42,43 and 44 carried by the upper end of the plunger 37.

The vertically movable plunger 37 is provided on one side with a toothedrack 47 which is engaged by an elongated gear 48, substantially one halfof the gear 48 being a driven gear meshing with the toothed rack 47 onthe plunger 37. The other half of the gear 48 forms a driving gear. Thegear 48 is journaled in suitable bearings 49 carried by the housing 30and they and the gear 48 are enclosed by plates 50 suitably secured inplace. Rack teeth 51 on a longitudinally movable rack 52 mesh with thedriving gear portion of the gear 48. The exterior of the rack 52 issplined to engage internal splines on spline bearings 54 suitablysecured in a longitudinally extending opening 53 in the housing 30 toprevent rotation of the rack. The splined rack 52 is secured by suitableadjustable couplings 55 to the longitudinally movable rod 25. Where twofeed bars 19 are used, a longitudinally movable rod 25 is provided foreach row of lifter mechanisms. Both rods 25 are driven from a common camdrive and are thus actuated simultaneously.

With the parts of the lifter mechanism in the position illustrated inFIGS. 4 to 7, the plunger 37 is in its lowered position and, hence, thefeed bar 19 is in its lowered position. When the rack 52 is moved to theleft by the longitudinally reciprocatable rod 25, the driving portion ofthe gear 48 is rotated in a clockwise direction as illustrated in FIG. 6to cause the driven portion of the gear 48 to raise the plunger 37 and,hence, the feed bar 19 supported by the supporting and guide rollers 42,43 and 44 carried by the bracket 41 which is secured to the upper end ofthe plunger 37. When the rack 52 is moved in the opposite direction tothe right by the longitudinally reciprocatable rod 25, the gear 48 isrotated in the counterclockwise direction to lower the plunger 37 and,hence, the feed bar 19. Thus, by longitudinally reciprocating the rack52 in one direction and the opposite direction the feed bar 19 is raisedand lowered, the longitudinal reciprocation of the rack 52 beingaccomplished by the longitudinal reciprocation of the rod 25.

A manifold 56, to which compressed air is suitably supplied, extendsalong the length of the press adjacent the various lifter mechanisms 22and suitable connections 57 are made from this manifold 56 to a passage58 in the downwardly extending portion 31 of the lifter housing 30 forsupplying compressed air below the sleeve 31 under the plunger 37. Thiscompressed air normally exerts an upward force on the plunger 37 forsupporting much of the load of the feed bar 19 and the mechanismscarried thereby. As a result, minimum stress is applied to the rack 52,the gear 48 and the toothed rack 47 of the plunger 37 and ready raisingand lowering of the feed bar 19 and the mechanisms carried thereby isprovided with minimum force applied to the longitudinally reciprocatablerod 25. By adjusting the adjustable connections 55, the positions of therack 52 and, hence, the plunger 37 may be adjusted with respect to theposition of the longitudinally reciprocatable rod 25. The stroke lengthof the reciprocatable rod 25 may be infinitely adjustable within apredetermined range so that the amount of lift motion may be varied tosuit the requirements of the parts to be produced. The number of liftermechanisms may be selected to suit the length of the feed bars 19 andthe racks 52 thereof may be connected together by the threaded couplings55.

The gripper mechanism generally designated at 20 in FIGS. 4 to 13includes a gripper mechanism housing 62. This housing 62, as illustratedin FIGS. 8 to 13, includes a transversely extending opening 63 in whichinternally splined bearing members 64 are mounted. Slidably mounted inthese bearing members 64 is an externally splined hollow first actuatorrod 65, the splines permitting longitudinal sliding movement of thefirst actuator rod 65 but preventing rotation thereof. A side of thehollow first actuator rod 65 is milled out as indicated at 66 and oneside of this milled portion 66 of the hollow actuator rod 65 is providedwith rack teeth 67. The other side of said side of the hollow actuatorrod 65, which is also milled out as indicated at 8, provides a circularcam slot which in turn is provided with a recess 69 and a shoulder 70 inthe form of a modified involute. A second actuator rod 71 islongitudinally slidable in the hollow first actuator rod 65 and it isprovided with rack teeth 72 which extend to a greater length to the leftthan the rack teeth 67 in the first actuator rod 65. The end of thesecond actuator rod 71 has an annular shoulder 73 which is adapted toengage the corresponding end of the first actuator rod 65 when saidactuator rods are in their retracted and advanced positions. The secondactuator rod 71 is provided with an extension 74 beyond the shoulder 73for operating the fingers of the gripper finger assembly 21.

A vertically arranged pin 76 is supported in the gripper mechanismhousing 62 by the bottom wall thereof and by a cover 77 suitably securedin place on the housing 62, a key holding the pin from longitudinal androtative movement. A combination gear and cam member 78 is rotatablymounted on the pin 76 by suitable bearings. The combination gear and cammember 78 has a driving gear 79, a driven gear 80 and a cam 81. A rack83 is longitudinally slidably mounted in the housing 62 and it isprovided with rack teeth 84 which mesh with the driving gear teeth 79.The rack 83 is longitudinally provided with a hole for receiving thelongitudinally reciprocatable rod 24 and is adjustably connected alongthe rod 24 by nuts 85 threaded on the rod 24. Thus, as the rod 24 isreciprocated, the rack 83 drives the driving gear 79. The rack 83 isadjustably mounted on the rod 24 so that each gripper mechanism may beadjusted and set independently of all others. Thus, adjustment of onegripper mechanism will not affect the setting of others.

With the parts in the position illustrated in FIGS. 4 to 11, thelongitudinally reciprocatable rod 24 and rack 83 are in the right handposition and the first actuator rod and the second actuator rod 71 arein the retracted position. As the longitudinally reciprocatable rod 24is moved to the left, the driving gear 79 is rotated by the rack 83 torotate the driven gear 80 and the cam 81. This rotation of the drivengear 80 which meshes with the racks 67 and 72 on the actuator rods 65and 71 laterally advances these actuator rods from their retractedpoSitions as illustrated in FIG. 11 to substantially their advancedpositions as illustrated in FIG. 12. When the actuator rods 65 and 71are so moved to substantially their advanced positions as illustrated inFIG. 12, the rack teeth 67 on the first actuator rod 65 disengaging thedriven gear teeth 80 so that the first actuator rod 65 cannot beadvanced any further thereby. At this point the leading edge of the cam'81 having a modified involute form engages the shoulder of modifiedinvolute form in the recess 69 of the cam slot 68 in the first actuatorrod 65 to provide a slight amount of additional forward motion to thefirst actuator rod 65. When, however, the leading edge of the cam 81disengages the shoulder 70 as illustrated in FIG. 13, the cam 81 isengaged by the circular cam slot 68 in the actuator rod 65 and, hence,further advance of the first actuator rod 65 is stopped, the cam 81cooperating with the circular cam slot 68 to lock the first actuator rod65 in the advanced position. As the combination cam and gear member 78is further rotated, the driven gear which is still in mesh with the rackteeth 72 on the second actuator rod 71, causes continued advance of thesecond actuator rod 71 toward a projected position. Such continuedadvancing movement of the second actuator rod 71 beyond the advancedposition to the projected position operates to cause the fingers of thegripper fingers mechanism 21 to close as will be explained more fullyhereafter.

When the longitudinally reciprocatable rod 24 is moved in the oppositedirection to the right, the combination gear and cam member 78 isrotated in the opposite direction to retract the second actuator rod 71from its projected position to its advanced position. When the secondactuator rod is thus retracted to its advanced position, the leadingedge of the cam 81 is returned beyond the shoulder 70 in the slot 69 inthe first actuator rod 65 and the shoulder 73 on the first actuator rod71 engages the end of the first actuator rod 62. This causes the firstactuator rod 65 to be retracted somewhat from its advanced position sothat the rack teeth 67 thereof are re-engaged by the driven gear 80 topositively drive the first actuator rod 65 and also the second actuatorrod 71 from their advanced positions to their retracted positions asillustrated in FIG. 11. When the first actuator rod 65 is beinginitially retracted, the modified involute leading edge of the cam 81and the modified involute shoulder 70 on the rod 65 engage to insureproper reengagement of the rack teeth 67 With the teeth of the drivengear 80. Thus, upon movement of the longitudinally reciprocatable rod 24to the left, the first and second actuator rods 65 and 71 are driven totheir advanced position from their retracted position, the firstactuator rod 65 is stopped or locked in its advanced position and thesecond actuator rod 71 is advanced beyond the advanced position to theprojected position. Upon movement of the longitudinally reciprocatablerod 24 in the opposite direction to the right the second actuator rod 71is retracted from its projected position to its advanced position, thestopping or locking means for the second actuator rod 71 is released andboth the first actuator rod 65 and the second actuator rod 71 areretracted from their advanced position to their retracted position.

The gripper finger mechanism generally designated at 21 in FIGS. 7, 8,9, 11 and 12 includes a bracket 87 which fits over the splined end ofthe first actuator rod 65. Adjacent its end, the first actuator rod 65is provided with a first groove for receiving a snap ring 89 and asecond wider groove for rotatably receiving an internally splined ring88 (FIG. 14). The ring 88 is drawn against the snap ring by threeequally radially spaced screws threaded into the bracket 87 to clamp thebracket 87 in place, and when this occurs the internal splines in thering 88 engage the external splines on the first actuator rod 65 betweenthe grooves therein to lock the bracket 87 against rotation. There are20 splines on the rod 65 and in the ring 88 and since three equallyspaced screws are utilized (FIG. 14), the bracket 87 may be clamped in60 different desired rotative positions on the rod 65. The bracket 87has a pair of spaced ears 98 and a pair of gripper fingers 99 arearranged between and pivoted to the ears 98 by pivots 100. The pivotedgripper fingers 99 are connected by links 101 to a bracket 102 carriedby the projection 74 on the second actuator rod '71, the bracket 102being secured in place on the projection 74 by a snap ring 103.

en both of the actuator rods 65 and 71 are in their retracted positionsand in their advanced positions with the shoulder 73 on the secondactuator rod 71 engaging the first actuator rod 65, the gripper fingers99 are opened as illustrated. However, when the first and secondactuator rods 65 and 71 are advanced to their advanced position and thesecond actuator rod 71 is advanced beyond the advanced position to theprojected position, the bracket 102 is moved outwardly to cause thelinks 101 to close the gripper fingers 99. When the second actuator rod71 is retracted from the projected position to the advanced positionwhere the shoulder 73 on the second actuator rod 71 engages the end ofthe first actuator rod 65, the bracket 102 on the second actuator rod 71is retracted to cause the links 101 to open the gripper fingers 99. Toaid in adjusting the gripper finger mechanisms in their work grippingpositions, the opposite ends of the second actuator rods 71 are threadedand provided with nuts 71A. In setting up the transfer assembly, thelongitudinally reciprocatable rod 24 is moved to the left to advance thegripper finger mechanisms 21 and close the gripper fingers thereof andone of the nuts 85 on the rod 24 adjacent each gripper mechanism 20 isbacked off to allow desired setting of the fingers in their closedpositions. The nuts 71A are then drawn up against the end of the firstactuator rod 65 and locked in place to fix the set positions of theclosed fingers for the particular work pieces gripped thereby. Then thenuts 85 on the rod 24 are drawn up against the racks 83. In this way theclosed positions of the gripper fingers may be individually accuratelyset. Also, by utilizing the nuts 71A the set position is always assuredeven though it may be necessary to back off the nuts 85 to release afaulty work piece from between the fingers should this occur and berequired.

Referring to FIGS. 4 and 5, the feed bars 19 carry a plurality oflubricating fittings 106 for supplying lubricant through connections 107to the moving parts of the gripper mechanisms 20, suitable lubricantbeing supplied to the lubricating fittings 106 from a lubricant supplyline 108. The feed bars 19 also carry terminal boxes 110 having leads111 extending to the gripper fingers for providing an electrical signalto indicate that the work pieces are properly gripped by the gripperfingers of the gripper assembly. In the even that the work pieces arenot properly gripped the signal operates to shut down the press.

While for purposes of illustration one form of this invention has beendisclosed, other forms thereof may become apparent to those skilled inthe art reference to this disclosure.

I claim: 1

1. In a transfer assembly for a press for gripping and transferring workpieces from station to station along the press and including at leastone longitudinally movable feed bar, at least one gripper mechanismcarried by said at least one feed bar for longitudinally moving gripperfinger mechanisms having gripper fingers to grip and release work piecesfor transferring the work pieces as said at least one feed bar islongitudinally moved and at least one lifter mechanism for raising andlowering said at least one longitudinally movable feed bar, theimprovement wherein each said lifter mechanism includes a lifterhousing, a plunger vertically slidably mounted in said housing andextending upwardly therefrom, a bracket carried by the upper end of saidplunger and having supporting and guiding rollers thereon, guide trackson said at least one longitudinally movable feed bar engageable withsaid supporting and guiding rollers for supporting and guiding said atleast one feed bar for longitudinal movement, and means for raising andlowering said plunger for raising and lowering said at least onelongitudinally movable feed bar.

2. The combination of claim 1 wherein said means for raising andlowering said plunger includes a driven gear in said housing androtatable in opposite directions, and a rack on said plunger engageablewith said driven gear for raising and lowering the plunger as the gearis rotated.

3. The combination of claim 2 including a driving gear in the housingassociated with said driven gear for driving the same, and at least onelongitudinally reciprocatable rod extending lengthwise of said at leastone feed bar into the housing, and a rack on said at least onelongitudinally reciprocatable rod engageable with said driving gear fordriving the same to raise and lower said plunger and hence said at leastone longitudinally movable feed bar.

4. The combination of claim 1 including means supplying air underpressure below said plunger to in supporting the load carried by saidplunger.

5. The combination of claim 2 including means for supplying air underpressure below said plunger to aid in supporting the load carried bysaid plunger.

6. The combination of claim 3 including means supplying air underpressure below said plunger to in supporting the load carried by saidplunger.

7. The combination of claim 1 including means for longitudinally movingsaid at least one feed bar in one direction when said at least one feedbar is in a raised position and for longitudinally moving said at leastone feed bar in the opposite direction when said at least one feed baris in a lowered position.

8. The combination of claim 3 including means for longitudinally movingsaid at least one feed bar in one direction when said at least one feedbar is in a raised position and for longitudinally moving said at leastone feed bar in the opposite direction when said at least one feed baris in a lowered position.

9. The combination of claim 1 wherein the guide tracks on said at leastone longitudinally movable feed bar extend longitudinally therealong andproject laterally therefrom, and said supporting and guiding rollers onsaid bracket are arranged below, above and laterally of said guidetracks.

10. The combination of claim 2 wherein the guide tracks on said at leastone longitudinally movable feed bar extend longitudinally therealong andproject laterally therefrom, and said supporting and guiding rollers onsaid bracket are arranged below, above and laterally of said guidetracks.

11. The combination of claim 3 wherein the guide tracks on said at leaston longitudinally movable feed bar for aid for aid extend longitudinallytherealong and project laterally therefrom, and said supporting andguiding rollers on said bracket are arranged below, above and laterallyof said guide tracks.

12. The combination of claim 10 including means for longitudinallymoving said at least one feed bar in one direction when said lat leastone feed bar is in a raised position and for longitudinally moving saidat least one feed bar in the opposite direction when said at least onefeed bar is in a lowered position.

13. The combination of claim 11 including means for longitudinallymoving said at least one feed bar in one direction when said at leastone feed bar is in a raised position and for longitudinally moving saidat least one feed bar in the opposite direction when said at least onefeed bar is in a lowered position.

14. The combination of claim 1 wherein said at least one grippermechanism carried by said at least one feed bar includes means forlaterally moving said gripper finger mechanisms between advanced andretracted positions and for closing and opening the fingers thereof whenin advanced position.

15. The combination of claim 7 wherein said at least one grippermechanism carried by said at least one feed bar includes means forlaterally moving said gripper finger mechanisms between advanced andretracted positions and for closing and opening the fingers thereof whenin advanced position and means for operating said at least one grippermechanism to advance said gripper finger mechanisms and close thefingers thereof before said at least one feed bar is raised and beforeit is longitudinally moved in one direction and for operating said atleast one gripper finger mechanism to open the fingers thereof andretract the same after said at least one feed bar is lowered and beforeit is longitudinally moved in the opposite direction.

References Cited UNITED STATES PATENTS 3,001,651 9/1961 Fekete 2l413,165,192 1/1965 Wallis 2141 GERALD M. FORLENZA, Primary Examiner 13.5.C1. X.R. 198-218

